In the past decade, innovations in the diagnosis of cardiovascular disease have migrated from external imaging processes to internal, catheterization-based, diagnostic processes. Diagnosis of cardiovascular disease has been performed through angiogram imaging wherein a radiopaque dye is injected into a vasculature and a live x-ray image is taken of the portions of the cardiovascular system of interest. Magnetic resonance imaging (MRI) has also been utilized as well. More recently, however, diagnostic equipment and processes have been developed for diagnosing vasculature blockages and other vasculature disease by means of ultra-miniature sensors placed upon a distal end of a flexible elongate member such as a catheter, or a guide wire used for catheterization procedures.
One such ultra-miniature sensor device is a pressure sensor mounted upon the distal end of a guide wire. An example of such a pressure sensor is provided in Corl et al. U.S. Pat. No. 6,106,476, the teachings of which are expressly incorporated herein by reference in their entirety. Such intravascular pressure sensor measures blood pressure at various points within the vasculature to facilitate locating and determining the severity of stenoses or other disruptors of blood flow within the vessels of the human body. Such devices are commonly used to determine the effectiveness of an angioplasty procedure by placing the pressure sensor proximate a stenosis and measuring a pressure difference indicating a partial blockage of the vessel.
As one can imagine, the aforementioned intravascular pressure sensors are utilized in operating room environments including many types of sensors and equipment for diagnosing and treating cardiovascular disease. Clearly, the room for error is very limited. Therefore, there is substantial interest in simplifying every aspect of the operating room to reduce the incidence of errors.
In a known prior intravascular pressure sensor-to-physiological monitor interface arrangement, marketed by JOMED Inc. of Rancho Cordova, Calif., and depicted in FIG. 1, a signal conditioning interface, comprising an amplifier module 10 (e.g., the Model 7000 Patient Cable) and a WAVEMAP processor box 12, is interposed between a physiology monitor 14 and a WAVEWIRE pressure sensing guide wire 16. The guide wire 16 is a disposable device connected via a connector 15 to the amplifier module 10. The amplifier module 10 receives power and an excitation signal through two separate and distinct electrically conductive lines within cable 17 connected to distinct output leads of the WAVEMAP processor box 12. The WAVEMAP processor box receives power from a standard wall outlet 18 via a standard three-pronged (grounded) power cord 20 plugged into the wall outlet 18. Though not shown in the drawing, the physiology monitor is powered via standard AC wall outlet power as well.
The WAVEMAP processor box 12 includes a separate and distinct signal interface connected to the physiology monitor 14. The WAVEMAP processor box receives a differential voltage excitation signal (either AC or DC) from the physiology monitor 14 via a cable 22. The excitation signal transmitted via the cable 22 is considerably lower power than the AC power deliverable to the WAVEMAP processor box 12 from the wall outlet 18 via the power cord 20. The cable 22 also transmits a signal representing sensed pressure (5 microvolts/mmHG) from the WAVEMAP processor box 12 to the physiology monitor 14. Yet another cable 24 transmits an aortic pressure (Pa) sensed by another device, from the physiology monitor 14 to the WAVEMAP processor box 12. The arrangement illustrated in FIG. 1 utilizes a rotary connector such as described in U.S. Pat. Nos. 5,348,481 and 5,178,159 to connect the guide wire to the amplifier module. This type of rotary connector is awkward to manipulate and requires high insertion forces to place the guide wire in the connector.